The goal o? these studies is to elucidate the action of selected peptide growth factors on adult articular cartilage. Bovine articular cartilage in serum-free organ culture will be used to evaluate the effect of selected growth factors, alone and in combinations, on chondrocyte matrix and DNA synthetic activity. Those factors that show the greatest anabolic effects in bovine cartilage organ culture will then be used to test the capacity of normal and osteoarthritic human cartilage to mount a reparative response in vitro. We hypothesize that the actions of certain growth factors are additive or synergistic and that there exists optimal combinations and doses of these factors for producing maximum anabolic effects in articular cartilage. If the data from these studies support this hypothesis, then Phase II testing of the reparative capacity of these factors in models of joint disease in vivo will be strongly indicated.